Objective: To review inferior vena cava (IVC) filter retrieval practice at our institution, the Royal London Hospital, and measure changes following a quality improvement intervention. IVC filters are a preventive treatment for pulmonary embolism when anticoagulation is ineffective/contraindicated. Unless permanent filtration is required, all filters should undergo attempted retrieval within manufacturer’s recommendations with a success rate of ≥80 %. Methods: Retrospective audit of filters inserted between 2011 and 2014, followed by a quality improvement intervention and a second audit between 2015 and 2017. Clinical–radiological data were analysed using the Picture Archiving and Communication System and electronic patient records. Results: During the first audit, filter retrieval was attempted in 92% of cases, of which 82% underwent the procedure within manufacturer's recommendations and 86% were successful. During the second audit, an improvement across indicators was seen. Retrieval increased by 3% and was attempted in 95% of cases (92% of which were within manufacturer’s guidelines). Rate of retrievals within manufacturer’s guidelines increased by 10%. Filter retrieval success rate increased by 11% - to 97%. Conclusions: IVC filter retrieval practice at a single institution can be improved by implementing a simple audit intervention. Advances in knowledge: Filter retrieval practice has clinical and medicolegal implications. A simple quality intervention can substantially improve overall practice.

Introduction Osteoid osteoma is a benign condition of the bone, usually affecting young males. This retrospective study explores the demographics of osteoid osteomas in the Northern Irish population. It also aims to audit the practice of CT-guided radiofrequency ablation of osteoid osteomas at a major orthopaedic centre in Belfast, Northern Ireland, and to investigate the possible causes of treatment failure. Methods Forty-seven osteoid osteoma patients, diagnosed based on clinico-radiologic features and treated with CT-guided radiofrequency ablation, were found eligible for inclusion and analysis. We collected data from electronic health records (March 2011 to May 2022) and reviewed the radiological images and associated reports. Information about demographics, clinical indices, operative technique, clinical outcomes, biopsy results, and follow-up were also gathered. Data were then analysed using IBM SPSS Statistics for Mac, version 28.0.1.1 (14) (IBM Corp., Armonk, NY). Results The average age of patients was 19.3 years, with a male-to-female predilection of 2.1:1. The proximal and mid-tibial shafts were the most frequently involved sites. On average, patients had symptoms for 15.6 months, while the mean treatment delay period was 6.9 months. Primary clinical success was observed in 37 patients (78.7%), while ten patients had a clinical failure. Two out of the 10 patients with treatment failure underwent subsequent successful ablations, raising the secondary clinical success rate to (83.0%). Chi-Square association tests found no correlation between primary treatment outcomes and other qualitative variables (gender, bone type, lesion location, and Kayser classification). Moreover, binary logistic regression tests found no predictability of age and treatment delay on treatment outcomes. The overall observed complication rate was 4%, with only one significant side effect reported (third-degree skin burn). Conclusion We concluded that the demographics of osteoid osteomas in the Northern Irish population are comparable to what is previously established in the literature. Furthermore, we reasoned that CT-guided radiofrequency ablation is an efficient, safe, and effective minimally invasive technique in the management of osteoid osteomas.